During a surgical procedure, it is advantageous in advance of the intervention to fix and to mark the accurate intervention position as a function of the anatomy of a patient and as a function of the type of operation so that no organs situated in the treatment area are damaged by the operation.
DE 100 57 027 A1 discloses for this purpose a marking method with the aid of which a penetration point and/or penetration angle at an examination object can be identified by a laser beam of a laser light sight. The laser light sight is assigned in this case to a C arm of an x-ray device, and can be adjusted in the plane defined by the C arm. In advance of the treatment, a planning scan of the area to be treated is carried out in order to identify the penetration point. Subsequently, there is marked in the volume image produced during the planning scan an intervention position on the basis of which the laser light sight is adjusted such that the intervention position marked in the volume image corresponds as well as possible to the position identified by the laser beam of the laser light sight.
The calculation of the adjusting positions of the laser light sight that are required for this purpose is possible only with a substantial numerical outlay and given accurate knowledge of the position of the laser light sight with reference to the recording system or with reference to the volume image produced.